• AIT Austrian Institute of Technology • University for Natural Resources and Life Sciences Vienna, Austria• LFZ Klosterneuburg• AGES Wien

Immobilization of copper in vineyard soils –the role of the organic additives

biochar and compost

Gerhard Soja, Franz Zehetner, Katharina Keiblinger, Franz Rosner,Florian Faber, Georg Dersch, Vladimir Fristak

The Bordeaux mixture:Cu as active ingredientinhibits the germination offungal spores – preventiveaction

Pre-WW II: Cu input rates tovineyard soils reached levels up to50 kg ha-1 yr-1

2Source: Gallica Digital Library

Cu-concentrations in the soils ofAustrian wine-growing regions Analytical Basis

comprehensive soil analysis survey about Cu-concentrations in agricultural regions

EDTA-extractable Cu (= exchangeable Cu) 75 % percentile for all analytical results: 61-75 EDTA-Cu (mg.kg-1) in

the most important wine growing regions (=11 000 of 45 000 ha vineyards)

3Source: www.oewm.at; Berger et al., 2012

The Wachau valley of the riverDanube 26 % of Wachau vineyard soils show >150 mg Cu kg-1 (= 390 ha;

Berger et al., 2012)

4

Austrian standard foragricultural / horticulturalsoils: 100 mg Cu kg-1

Potential benefits of organic addives(compost, biochar)

Reduction of Cu-availability (= general project objective): Lower ecotoxicity for soil cover crops or for re-planting of a new

vineyard Higher activity for soil life, including rhizobia

Increase of soil organic matter (Corg): Erosion reduction, better infiltration Higher water storage capacity Carbon sequestration Hypothesis: lower release of spores of soil fungi

5

Methodology of the research projectKUSTAW (copper stabilization in vineyard soils)

Lab experiments Sorption behaviour Microbiological effects

Greenhouse pot experiment Additive combinations Cu-translocation, 1 vine + soil cover crops

Field experiment 1 Application technology

Field experiment 2 Cu-translocation to soil cover crops, soil microbiology, phytopathology,

grape and wine analysis

6

7

(sandy soil, pH 7.3) (soil rich in Corg, pH 6.5)

Source: Deinhofer, 2015

Lab results I:Effects of different additives on exchangeable Cuand ionic Cu

Effect of pH-shift: clearer Cu-reductionsin more acidic soil

In acidic soil reductionof ionic Cu is still more apparent than ofexchangeable Cu

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3.0

3.5

4.0

4.5

5.0

0 65 130 251

Qeq

(mg

g-1 )

DOC (mg L-1)

Rossatz Rossatz + 3% BC

4.0

4.5

5.0

5.5

6.0

0 65 130 251

Qeq

(mg

g-1 )

DOC (mg L-1)

Stroh Stroh + 3% BC

Grey columns: soil onlyRed columns: soil + 3 % biochar

DOC was added as extract ofhumic acids from forest litter, in combination with 300 mg Cu l-1

More DOC more complexesmore sorption to soil-clay mineralcomplexes

Source: Bell, 2016

Lab results II:Analysis of Cu-DOC sorption interactions

(sandy soil, pH 7.3)

(soil rich in Corg, pH 6.5)

Greenhouse pot experiment

2 soils, differing in pH (6.5 and 7.3) elevated copper (110 and 251 mg EDTA-Cu kg-1) humus (5.0 vs. 1.5 % SOM)

8-10 treatments each n = 4 Seepage water collection with suction plate

9

10

PLFA used as indicator formicrobiological activity Additives were more beneficial

in the sandy soil, poor in Corg Some enzymes (e.g.

peroxidase) are moreexpressed if there is an easilyavailable C source at themodified biochar surface

Pot experiment:Effects of different additives on soilenzymatic activity

Source: Johnen, 2015

(sandy soil, pH 7.3)

(soil rich in Corg, pH 6.5)

(sandy soil, pH 7.3)

(soil rich in Corg, pH 6.5)

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Source: Keiblinger, 2016

y = 1152.4x‐0.603R² = 0.9689

0

100

200

300

400

500

600

700

0 1000 2000 3000 4000EDTA‐Cu

Acremonium OTUs L‐soil

y = 8489x‐0.228R² = 0.8219

0

1000

2000

3000

4000

5000

6000

7000

8000

0 1000 2000 3000 4000EDTA‐Cu

Fusarium OTUs L‐soil

y = 4345.8x‐0.711R² = 0.831

0

500

1000

1500

2000

2500

0 1000 2000 3000 4000EDTA‐Cu

Dactylonectria OTUs L‐soil

y = 13.772x0.6327R² = 0.9035

0

500

1000

1500

2000

2500

3000

0 1000 2000 3000 4000EDTA‐Cu

Plectosphaerella OTUs D‐soil

y = 0.1326x1.0573R² = 0.9025

0

200

400

600

800

1000

1200

1400

0 1000 2000 3000 4000EDTA‐Cu

Pseudogymnoascus OTUs D‐soil

0

2000

4000

6000

8000

10000

12000

1 10 100 1000 10000Cu EDTA

Thelebolus OTUs L‐soil

Wurzel PathogeneWurzel‐ und Pflanzen Pathogene

Pflanzenparasiten, Endophyten & Biocontrol

Saprotrophe & Ericoide Mykorrhiza

Saprotrophe

Wurzel Pathogene

Correlation soil fungi and soil Cu-concentration

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Cu speciation in Cu-impacted soilwith organic additives

Cu in 0.01 M CaCl2 Soil pH = 7.3 Proportion of Cu2+ (Visual Minteq)

Source: Deinhofer, 2015

Seepage water analysis from the pot experiment

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01020304050607080

DOC [m

g l‐1]

Additive

DOC in seepage water (2nd sampling)

01020304050607080

DOC [m

g l‐1]

Additive

DOC in seepage water (1st sampling)

Total Cu in seepage water 2

Cu2+ in seepage water 2

Green: sandy neutral soil; blue: acidic soil, rich in Corg

Sou

rce:

Cha

mie

r-Glis

czin

ski,

2016

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Field experiment 1 (application technique): before soilincorporation

Field experiment 1 (application technique): after soilincorporation

Effects of different soil incorporation techniques on soil bulkdensity (biochar : compost = 1 : 1 (40 t ha-1))

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Bodenfräse Grubber Spatenpflug oberfl. Aufbringung Kontrolle

Lage

rung

sdic

hte

[g/c

m3 ]

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6a a bab ab

Rotary hoe tooth cultivator spade plough surface spread no application

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Field experiment 2: additive comparison

ControlBiochar

Biochar:Compost = 1:1Biochar:Compost = 1:1

Compost

Green cover crops in the field 2015: Biochar reduced Cu uptake into the rootsbut not in combination with compost

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0

20

40

60

80

100

120

140

Control Biochar (BC) Compost (CP) BC/CP 4 kgm‐2

BC/CP 10 kgm‐2

Copp

er[m

g kg

‐1  ]

Cu in Trifolium repens roots

Source: Chamier-Glisczinski, 2016

Green cover crops in the field 2016: Biochar again reduced Cu uptake into the rootsbut not to above-ground parts

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Copper in green cover crops: Lolium perenne

Contr

olCo

mpos

t

4 kg/m

² mixt

ure

10 kg

/m² m

ixture

Bioch

ar

Contr

olCo

mpos

t

4 kg/m

² mixt

ure

10 kg

/m² m

ixture

Bioch

ar

Cu

(mg

/ kg)

0

20

40

60

80

100

120

140c c c c c a ab a bc ab

L E A V E S R O O T S

Sou

rce:

Mlin

kov,

201

6

19

Sequential extraction of Cu from rhizosphere soil after 13 months in the field

Contr

ol

Comp

ost

4 kg/m

² mixt

ure10

kg/m

² mixt

ure

Bioch

ar

% o

f tot

al C

u

0

10

20

30

40

50

60

a ab ab b ab

acid-exchangeable fraction (weak acetic acid)

Contr

ol

Comp

ost

4 kg/m

² mixt

ure10

kg/m

² mixt

ure

Bioch

ar

% o

f tot

al C

u

0

10

20

30

40

50

60a ab b b b

reducible fraction (hydroxyl amine)

Contr

ol

Comp

ost

4 kg/m

² mixt

ure10

kg/m

² mixt

ure

Bioch

ar

% o

f tot

al C

u

0

10

20

30

40

50

60ab b ab ab a

residual fraction (aqua regia)

Contr

ol

Comp

ost

4 kg/m

² mixt

ure10

kg/m

² mixt

ure

Bioch

ar

% o

f tot

al C

u

0

10

20

30

40

50

60b a a a a

oxidizable fraction (hydrogen peroxide)

Biochar reduced theproportionof Cu in themoreavailablefractions

Sou

rce:

Mlin

kov,

201

6

Soil characteristics determine the efficacy of different additive applications: especially pH, Corg-content

Complexation of Cu with soil organic matter determines theavailability of Cu

Surface modification of biochar was less important for Cusorption than the organic complexation option

Additives have more benefits for reducing theecotoxicologically relevant Cu2+ fraction, but not the mobile fraction of total Cu

Effects appear clearer in acidic soils than in neutral soils Biochar without compost or high doses of biochar/compost

mixtures in the field reduce Cu uptake into the roots of covercrops

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Conclusions (and outlook)

21

Thank youfor your attention!